Probably Picard as a peacetime leader. He was cerebral, principled, empathetic, and had incredible determination and resolve. On a couple occasions, his interpretation of the Prime Directive was a little problematic ("Homeward" for one), but his defense of Data, his shut-down of that witchhunt, and his managing to break free of the Borg long enough to tell Data "sleep" certainly compensates.
As a wartime leader, Sisko. He understood the brutal pragmatism involved in such a conflict. And, peace or war, it was cool having a captain who was a family man. He certainly had the best character journey.
Janeway had some great moments ("Time's... up!") and did some awesome stuff, but she was a bit inconsistently written. And she seriously lost it in Equinox. And, you know, Tuvix.
Archer stepped on his you-know-what right and left. Including throwing the Valakians and Charles the Cogenitor under the bus.
Kirk was in a habit of demolishing societies and warping out of orbit while Vaal's followers probably expired very quickly because they had no idea how to take care of themselves, or the women on the "Spock's Brain" planet died almost as quickly because they didn't know how to live like cavemen.
Freeman seems competent, but she is a character in what is basically a fanfiction parody. Riker was straight up awesome in that Pakled party, but killing your own clone is still murder. Discovery keeps changing captains. That kid on Prodigy has a lot to learn. And Picard, or course, is Picard.
Even Jellico had a great moment when he sent those Cardassian invaders home with their tails between their legs, but his close-minded attitude and micromanaging tendencies are a serious issue. Still, give that guy a ship crewed by Datas and Worfs, and he'll "get it done".